Echocardiographic Markers of Mild Pulmonary Hypertension are not Correlated with Worse Respiratory Outcomes in Infants with Bronchiolitis

Pulmonary hypertension has been reported as a crucial factor in the pathophysiology of severe bronchiolitis. The aim of this study was to evaluate pulmonary artery pressure (PAP) in patients with bronchiolitis and to analyze their correlation with clinical outcomes. This prospective cohort study examined children admitted for bronchiolitis. PAP was assessed by right ventricle (RV) acceleration/ejection time ratio (AT/ET), isovolumic relaxation time, eccentricity index, and the presence of a pulmonary systolic notch. Pulmonary hypertension (PH) was considered if at least two altered parameters were present. Severity of clinical course was established by higher N-terminal (NT)-prohormone BNP (NT-proBNP) values, the need for positive pressure respiratory support (PPRS), and the duration of hospital admission. One hundred sixty-nine children were included in analysis. Sixty-eight patients (40%) required PPRS, and those patients had increased NT-proBNP values and worse tricuspid annular systolic excursion (TAPSE) compared to mild cases (p < 0.001and p < 0.001, respectively). Twenty-two (13%) cases had at least two altered parameters of PAP and met criteria for presumed PH, with no differences in NT-proBNP values, TAPSE, need for PPRS or hospital length of stay compared to normal PAP group (p = 0.98, p = 0.07, p = 0.94 and p = 0.64, respectively). We found no correlation between altered RV AT/ET and worse cardiac function, NT-proBNP values or hospital length of stay. In our cohort, the presence of echocardiographic findings of PH were not associated with worse clinical outcomes. Patients with severe bronchiolitis had higher values of NT-proBNP but, interestingly, no clear association with PH.